What I feel following my course of ZCP mods:
1. OEM non-ZCP's Comfort mode is really comfortable, and Normal mode, well, normal. However, the Sport is quite harsh because there is no dynamic control and all the small and big bumps feel harsh.

2. After ZCP coding done by Mike Benvo, the entire car became stiffer for all the three modes. Good thing is that the Sport mode becomes a lot more compliant over small bumps. Still harsh over large bumps but the control is much better.

3. After ZCP suspension install, the entire car now becomes softer than after just with the ZCP coding, which makes me think that the ZCP coding must be use in conjunction with the ZCP suspension dues to the strut-reading by the EDC computer. Now all three modes are back to OEM non-ZCP feel but the Sport mode is now a lot more compliant. The difference between Comfort and Sport is not as dramatic as with non-ZCP but you can still feel the difference, especially hard cornering.

Conclusion:
I think for anyone who'd like to retrofit ZCP-suspension to non-ZCP M3, you need to get both the suspension and ZCP EDC coding for the entire system to work correctly. Simply install ZCP suspension or just upgrade ZCP software is not enough because the computer might not be reading the strut correctly, evident from the fact that my ZCP-coded only becomes stiffer for all three modes. In this case, I think the ZCP-coded EDC computer interpreted non-ZCP strut to be under rebound (because non-ZCP is 10mm higher) and hence pre-stiffen the struts.

As far as the lowering goes, before ZCP suspension I had 2.5 fingers gap at front and 1 at the back. After the lowering, 2 front and 0.5 back.